Nanostructured flat lenses for display technologies

ABSTRACT

Embodiments described herein relate to display devices, e.g., virtual and augmented reality displays and applications. In one embodiment, a planar substrate has stepwise features formed thereon and emitter structures formed on each of the features. An encapsulating layer is disposed on the substrate and a plurality of uniform dielectric nanostructures are formed on the encapsulating layer. Virtual images generated by the apparatus disclosed herein provide for improved image clarity by reducing chromatic aberrations at an image plane.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/992,305, filed May 30, 2018, which claims benefit of IndianProvisional Patent Application No. 201741045374, filed Dec. 18, 2017,and Indian Provisional Patent Application No. 201741019417, filed Jun.2, 2017, both of which are hereby incorporated by reference in theirentirety.

BACKGROUND Field

Embodiments of the present disclosure generally relate to displaydevices for augmented and virtual reality applications. Morespecifically, embodiments described herein relate to structured lensesfor utilization in augmented and virtual reality displays.

Description of the Related Art

Augmented reality is generally considered to enable an experience inwhich a user can see through display lenses of glasses or otherhead-mounted display (HMD) devices to view the surrounding environment,yet also see images of virtual objects that are generated for displayand appear as part of the environment. Augmented reality can include anytype of input, such as audio and haptic inputs, as well as virtualimages, graphics, and video that enhances or augments the environmentthat the user experiences.

Virtual reality, however, is generally considered to be a computergenerated simulated environment in which a user has an apparent physicalpresence. A virtual reality experience can be generated in 3D and viewedwith a HMD, such as glasses of other wearable display devices that havenear-eye display panels as lenses to display a virtual realityenvironment that replaces an actual environment.

Near eye display panels have several technical challenges. For example,limited field of view, display clarity associated with chromaticaberrations, and other challenges persist in implementing virtualreality displays that are capable of enabling an immersive virtualexperience. More specifically, an optical path length difference, whichis the product of the geometric length of the path light and the indexof refraction of the medium through which the light propagates, mayexist when utilizing light of varying wavelengths. As such, optical pathlength difference of red, green, and blue light may not be preciselyfocused on an image plane which leads to the aforementioned chromaticaberration. Accordingly, as an emerging technology, there are manychallenges and design constraints present in fabricating displays forvirtual and augmented reality devices.

SUMMARY

In one embodiment, a display apparatus is provided. The apparatusincludes a substrate having a plurality of features formed thereon, afirst feature disposed in a first plane, and a first emitter structuredisposed on the first feature. The apparatus also includes a secondfeature disposed in a second plane different than the first plane, asecond emitter structure disposed on the second feature, a third featuredisposed in a third plane different than the first plane and the secondplane, and a third emitter structure disposed on the third feature. Anencapsulating layer is formed over the plurality of features and coupledto the substrate and a plurality of dielectric nanostructures are formedon the encapsulating layer.

In another embodiment, a display apparatus is provided. The apparatusincludes a substrate having a plurality of features formed thereon, afirst feature disposed in a first plane, a first emitter structuredisposed on the first feature, and a first encapsulating layer formedover the first emitter structure. The apparatus also includes a secondfeature disposed in a second plane different than the first plane, asecond emitter structure disposed on the second feature, and a secondencapsulating layer formed over the second emitter structure. Stillfurther, the apparatus includes a third feature disposed in a thirdplane different than the first plane and the second plane, a thirdemitter structure disposed on the third feature, and a thirdencapsulating layer formed over the third emitter structure. A pluralityof dielectric nanostructures are formed on the first encapsulatinglayer, the second encapsulating layer, and the third encapsulatinglayer.

In yet another embodiment, a display apparatus is provided. Theapparatus includes a substrate having a first surface and a secondsurface disposed opposite the first surface, wherein the first surfaceand the second surface are planar. A first emitter structure is disposedon the first surface, a second emitter structure is disposed on thefirst surface, and a third emitter structure is disposed on the firstsurface. An encapsulating layer is disposed over the first emitterstructure, the second emitter structure, and the third emitterstructure. A first plurality of dielectric nanostructures having firstdimensions are disposed on the encapsulating layer corresponding to aregion of the first emitter structure. A second plurality of dielectricnanostructures having second dimensions different than the firstdimensions are disposed on the encapsulating layer corresponding to aregion of the second emitter. A third plurality of dielectricnanostructures having third dimensions different than the firstdimensions and the second dimensions are disposed on the encapsulatinglayer corresponding to a region of the third emitter structures.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofits scope, may admit to other equally effective embodiments.

FIG. 1 is a schematic, cross-sectional view of a display apparatusaccording to an embodiment described herein.

FIG. 2 is a schematic, cross-sectional view of a display apparatusaccording to an embodiment described herein.

FIG. 3 is a schematic, cross-sectional view of a display apparatusaccording to an embodiment described herein.

FIG. 4A is a partial schematic plan view of a light emitting diode (LED)array according to an embodiment described herein.

FIG. 4B is a partial schematic plan view of the LED array of FIG. 4Awith nanolenses disposed on pixels of the LED array according to anembodiment described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

Embodiments described herein relate to display devices, e.g. virtual andaugmented reality devices and applications. In one embodiment, a planarsubstrate has stepwise features formed thereon and emitter structuresformed on each of the features. An encapsulating layer is disposed onthe substrate and a plurality of uniform dielectric nanostructures areformed on the encapsulating layer. Virtual images generated by theapparatus disclosed herein provide for improved image clarity byreducing chromatic aberrations at an image plane.

FIG. 1 is a schematic, cross-sectional view of a display apparatus 100according to an embodiment described herein. The display apparatus 100includes a substrate 102 having a plurality of stepwise features 112,114, 116 formed thereon. The substrate 102 is made of an opticallytransparent material, such as glass. Alternatively, the substrate 102may be made of a sapphire material. In another embodiment, the substrate102 may be made of an aluminum nitride material. The features 112, 114,116 are patterned and etched into the substrate 102 by patterning andetching tools. Examples of such tools are available form AppliedMaterials Inc., Santa Clara, Calif.

The features 112, 114, 116 are formed on the substrate 102 opposite aplanar surface 144 of the substrate 102. A first feature 112 defines asurface disposed in a first plane 146. A second feature 114 defines asurface disposed in a second plane 148. A third feature 116 defines asurface disposed in a third plane 150.

Each of the features 112, 114, 116 are disposed in planes different fromone another. For example, each feature 112, 114, 116 is disposed at aplane having a unique focal length to an image plane 132. The firstfeature 112 disposed at the first plane 146 has a first focal length 152from the first plane 146 to the image plane 132. The second feature 114disposed at the second plane 148 has a second focal length 154 from thesecond plane 148 to the image plane 132. The third feature 116 disposedat the third plane 150 has a third focal length 156 from the third plane150 to the image plane 132. The second focal length 154 is greater thanthe first focal length 152 and the third focal length 156 is greaterthan the second focal length 154. By varying the focal lengths 152, 154,156 of the features 112, 114, 116, respectively, pre-compensation forchromatic aberration is achieved as discussed in greater detail below.

A plurality of emitter structures 122, 124, 126 are formed on theplurality of features 112, 114. 116. A first emitter structure 122 isdisposed on the first feature 112. A second emitter structure 124 isdisposed on the second feature 114. A third emitter structure 126 isformed on the third feature 116. Each of the emitter structures 122,124, 126 generate light to form an image at the image plane 132. Forexample, the first emitter structure 122 emits light 138 which is imagedon the image plane 132, the second emitter structure 124 emits light 136which is imaged on the image plane 132, and the third emitter structure126 emits light 134 which is imaged on the image plane 132.

Examples of suitable devices for each of the emitter structures 122,124, 126 include, but are not limited to, liquid crystal display (LCD)devices, light emitting diode (LED) devices, and organic light emittingdiode (OLED) devices, among others. In one embodiment, the emitterstructures 122, 124, 126 comprise a pixel 104 and the first emitterstructure 122 is a first sub-pixel 106, the second emitter structure 124is a second sub-pixel 108, and the third emitter structure 126 is athird sub-pixel 110. In an alternative embodiment, each of the firstemitter structure 122, the second emitter structure 124, and the thirdemitter structure 126 may be considered pixels.

In one example, the first emitter structure 122 is configured togenerate light at a first wavelength having a first bandwidth. In oneembodiment, the first emitter structure 122 generates blue light. Thesecond emitter structure 124 is configured to generate light at a secondwavelength having a second bandwidth different from the first wavelengthand first bandwidth. In one embodiment, the second emitter structure 124generates green light. The third emitter structure 126 is configured togenerate light at a third wavelength having a third bandwidth differentfrom the first and second wavelengths and bandwidths, respectively. Inone embodiment, the third emitter structure 126 generates red light.

Each of the emitter structures 122, 124, 126 are disposed on arespective one of the features 112, 114, 116. As such, each of theemitter structures 122, 124, 126 are disposed a different focal lengthfrom the image plane 132. The planes 146, 148, 150 defined by thefeatures 112, 114, 116, respectively, and ultimately the color type ofemitter structure disposed on the features is determined by performingfinite-different time-domain simulations to determine a delta betweenthe planes 146, 148, 150.

For example, the first feature 112 which defines the first plane 146 hasa blue light emitter structure 122 disposed thereon. The second feature114 which defines the second plane 148 has a green light emitterstructure 124 disposed thereon. The third feature 116 which defines thethird plane 150 has a red light emitter structure 126 disposed thereon.In this example, a plane delta 118 between the first plane 146 and thesecond plane 148 is determined by an order of wavelength differencebetween the blue light wavelength and the green light wavelength.Similarly, a plane delta 120 between the second plane 148 and the thirdplane 150 is determined by an order of wavelength difference between thegreen light wavelength and the red light wavelength. As a result, therelative positions of the features 112, 114, 116, and thus, thecorresponding emitter structures 122, 124, 126, can be positionedrelative to the image plane 132 in order to pre-compensate for opticalpath length differences of light having various wavelengths.Accordingly, chromatic aberration at the image plane 132 is reduced andimage clarity is improved.

The display apparatus 100 further includes an encapsulating layer 128and a plurality of nanostructures 130 disposed on the encapsulatinglayer 128. The encapsulating layer 128 is fabricated from an opticallytransparent material and functions to encapsulate the emitter structures122, 124, 126 formed on the features 112, 114, 116. The encapsulatinglayer 128 has a first surface 142 and a second surface 140 disposedopposite the first surface 142. The first surface 142 and second surface140 are both planar and parallel to one another. The first surface 142is coupled to and disposed adjacent the substrate 102. In oneembodiment, the encapsulating layer 128 is disposed in contact with atleast one of the emitter structures, such as the first emitter structure122 with the shortest optical path length 152.

Due to the stepwise morphology of the features 112, 114, 116 and theplanar morphology of the encapsulating layer first surface 142, aninterstitial space 144 is formed between the second and third features114, 116, respectively, and the first surface 142 of the encapsulatinglayer 128. In one embodiment, the interstitial space 144 is filled witha gas, such as air or the like. In an alternative embodiment, theinterstitial space 144 is filled with a material having a refractiveindex similar to either a refractive index of the substrate material ora refractive index of the encapsulating layer material.

The plurality of nanostructures 130 are disposed on the second surface140 of the encapsulating layer 128. The plurality of nanostructures 130are formed from a dielectric material, such as ZnO materials, TiO₂materials, GaN materials, and combinations thereof. The dielectricmaterial may by crystalline or amorphous, depending upon the desiredoptical properties associated different crystallographic latticestructures (or lack thereof). Each nanostructure of the plurality ofnanostructures 130 is fabricated with substantially the same morphology.In other words, the plurality of nanostructures 130 are uniform. Themorphology of each nanostructure 130 may be columnar, pillar-like,cubic, or the like. A height, width, length, diameter, spacing, or otherphysical characteristic of individual nanostructures are substantiallysimilar to other nanostructures in the plurality of nanostructures 130.In one embodiment, a width/diameter of each nanostructure 130 is betweenabout 100 nm and about 350 nm, a height of each nanostructure 130 isbetween about 200 nm and about 300 nm, and spacing between adjacentnanostructures is between about 50 nm and about 250 nm.

The nanostructures 130 are deposited by various techniques dependingupon the type of dielectric material utilized to fabricate thenanostructures 130. Suitable deposition techniques include chemicalvapor deposition, physical vapor deposition, molecular beam epitaxy andthe like. Apparatus suitable for performing such deposition processesare tools available from Applied Materials, Inc., Santa Clara, Calif.Patterning of dielectric films deposited to form the nanostructures 130includes processes such as nano-imprint lithography, e-beam lithography,or other lithographic techniques suitable for forming the nanostructures130 with morphology sizes such as those described above. Thus,fabrication of uniform nanostructures 130 is more easily accomplishedthan forming unique morphology nanostructures.

Having pre-compensated for optical path length differences of differentwavelength light by utilizing the step-wise features 112, 114, 116, thenanostructures 130 can be utilized to additionally focus the light onthe image plane 132. For example, red light 134 emitted from the thirdemitter structure 126 is focused at the image plane 132, green light 136emitted from the second emitter structure 124 is focused at the imageplane 132, and blue light 138 emitted from the first emitter structure122 is focused at the image plane 132. As a result of the optical pathlength pre-compensation of the stepwise features 112, 114, 116 and thelight focusing characteristics of the nanostructures 130, an image canbe viewed from a viewer's perspective 101 at the image plane 132 withimproved clarity and without chromatic aberration. Accordingly, thelight 134, 136, 138 is imaged in the same plane (e.g. the image plane132) and a virtual image generated by the light in the plane can beviewed without any, or at least substantially reduced, chromaticaberration.

FIG. 2 is a schematic, cross-sectional view of a display apparatus 200according to an embodiment described herein. The display apparatus 200includes a plurality of encapsulating layers 202, 204, 206 disposed onthe emitter structures 122, 124, 126. For example, a first encapsulatinglayer 202 is disposed on and contacts the first emitter structure 122, asecond encapsulating layer 204 is disposed on and contacts the secondemitter structure 124, and a third encapsulating layer 206 is disposedon and contacts the third emitter structure 126. As such, the first,second, and third encapsulating layers 202, 204, 206, are orientedstep-wise similar to the step-wise orientation of the features 112, 114,116. The materials selected for the encapsulating layers 202, 204, 206are similar to those of the encapsulating layer 128.

A first plurality of nanostructures 208 are disposed on the firstencapsulating layer 202, a second plurality of nanostructures 210 aredisposed on the second encapsulating layer 204, and a third plurality ofnanostructures 212 are disposed on the third encapsulating layer 206.Similar to the nanostructures 130, each of the nanostructures 208, 210,212 are formed from a dielectric material and have a uniform morphology.Not unlike the display apparatus 100, display apparatus 200 utilizes theoptical path length pre-compensation of the step-wise features 112, 114,116 and the light focusing characteristics of the nanostructures 130 toenable viewing of an image from a viewer's perspective 101 at the imageplane 132 with improved clarity and without chromatic aberration.

FIG. 3 is a schematic, cross-sectional view of a display apparatus 300according to an embodiment described herein. The display apparatus 300includes a substrate 302 which has a first surface 304 and a secondsurface 306. The substrate 302 is substantially planar and the firstsurface 304 and second surface 306 are disposed opposite and parallel toone another. Materials utilized for the substrate 302 are similar tothose selected for the substrate 102 described supra.

A first emitter structure 308, a second emitter structure 310, and athird emitter structure 312 are disposed on the first surface 304 whichdefines a common plane. The emitter structures 308, 310, 312 may besimilar to the emitter structures 122, 124, 126 described above. Thesecond emitter structure 310 is disposed adjacent to the first emitterstructure 308 and the third emitter structure 312 is disposed adjacentto the second emitter structure 310. In one embodiment, the firstemitter structure 308 is configured to generate a blue light, the secondemitter structure 310 is configured to generate a green light, and thethird emitter structure 312 is configured to generate a red light.

An encapsulating layer 314, fabricated from materials similar to thosedescribed with regard to the encapsulating layer 128, is disposed overthe emitter structures 308, 310, 312. In one embodiment, theencapsulating layer 314 is disposed in contact with the emitterstructures 308, 310, 312. The encapsulating layer 314 is substantiallyplanar in morphology and has a substantially uniform thickness in allregions adjacent to the emitter structures 308, 310, 312.

A first plurality of nanostructures 316 are formed on the encapsulatinglayer 314 corresponding to a region of the first emitter structure 308,e.g. sub-pixel region 106 which is an area of the substrate 302corresponding to the first emitter structure 308. The firstnanostructures 316 share a uniform dimensional morphology (size, shape,and spacing) within the sub-pixel region 106. The dimensional morphologyof the first nanostructures 316 is selected based upon a wavelength oflight emitted from the first emitter structure 308 to compensate foroptical path length differences between light of different wavelengthsimaged at a singular image plane 322. For example, the firstnanostructures 316 have a dimensional morphology selected to image andfocus blue light 328 emitted from the first emitter structure 308 at theimage plane 322.

A second plurality of nanostructures 318 are formed on the encapsulatinglayer 314 corresponding to a region of the second emitter structure 310,e.g. sub-pixel region 108. The second nanostructures 318 share a uniformdimensional morphology within the sub-pixel region 108. Similar to thefirst nanostructures 316, the dimensional morphology of the secondnanostructures 318 is selected based upon a wavelength of light emittedfrom the second emitter structure 310 to compensate for optical pathlength differences between light of different wavelengths imaged at theimage plane 322. The dimensional morphology of the second nanostructures318 is different from the dimensional morphology of the firstnanostructures 316. For example, the second nanostructures 318 have adimensional morphology selected to image and focus green light 326emitted from the second emitter structure 310 at the image plane 322.

A third plurality of nanostructures 320 are formed on the encapsulatinglayer 314 corresponding to a region of the third emitter structure 312,e.g. sub-pixel region 110. The third nanostructures 320 share a uniformdimensional morphology within the sub-pixel region 110. Similar to thefirst and second nanostructures 316, 318, respectively, the dimensionalmorphology of the third nanostructures 320 is selected based upon awavelength of light emitted from the third emitter structure 312 tocompensate for optical path length differences between light ofdifferent wavelengths imaged at the image plane 322. The dimensionalmorphology of the third nanostructures 320 is different from thedimensional morphology of the first nanostructures 316 and the secondnanostructures 318. For example, the third nanostructures 320 have adimensional morphology selected to image and focus red light 324 emittedfrom the third emitter structure 312 at the image plane 322.

Accordingly, image display can be achieved by utilizing thenanostructures 316, 318, 320 which compensate for optical path lengthdifferences of light having different wavelengths and the light focusingcharacteristics of the nanostructures 316, 318, 320 to view an imagefrom a viewer's perspective 101 at the image plane 322 with improvedclarity and without chromatic aberration.

FIG. 4A is a partial schematic plan view of a light emitting diode (LED)array 400 according to an embodiment described herein. Examples ofsuitable LED arrays include, but are not limited to, LED devices andorganic light emitting diode (OLED) devices, among others. In oneembodiment, the LED array 400 includes a substrate 408 and has aplurality of pixels 402, 404, 406 disposed thereon. In one example, theLED array 400 is an OLED pentile array.

In one example, a first pixel 402 is configured to generate light at afirst wavelength having a first bandwidth. In one embodiment, the firstpixel 402 generates red light. A second pixel 404 is configured togenerate light at a second wavelength having a second bandwidthdifferent from the first wavelength and first bandwidth. In oneembodiment, the second pixel 404 generates blue light. A third pixel 406is configured to generate light at a third wavelength having a thirdbandwidth different from the first and second wavelengths andbandwidths, respectively. In one embodiment, the third pixel 406generates green light.

Each of the pixels 402, 404, 406 is arranged on the substrate 408 in apattern to form the array 400. In one embodiment, the pixels 402, 404,406 have a uniform size and distribution architecture. In anotherembodiment, the pixels 402, 404, 406 each have a unique size,respectively, and a uniform distribution pattern across the array 400.While the pixels 402, 404 are illustrated as having a predominantlyquadrilateral shape, it is contemplated that any desirable shape may beutilized for the pixels 402, 404. Similarly, while the pixels 406 areillustrated as having a circular or oblong shape, it is contemplatedthat any desirable shape may be utilized for the pixels 406.

FIG. 4B is a partial schematic plan view of the LED array 400 of FIG. 4Awith nanolenses 410, 414, 418 disposed on the pixels 402, 404, 406,respectively, of the LED array 400 according to an embodiment describedherein. A first nanolens 410 having a plurality of first nanostructures412 formed thereon is disposed on the first pixels 402. A secondnanolens 414 having a plurality of second nanostructures 416 formedthereon is disposed on the second pixels 404. A third nanolens 418having a plurality of third nanostructures 420 formed thereon isdisposed on the third pixels 406. Each of the nanolenses 410, 414, 418are sized and shaped to substantially correspond to the size and shapeof the corresponding underlying pixels 402, 404, 406.

In one embodiment, each of the nanolenses 410, 414, 418 aremonochromatic lenses. In this embodiment, the plurality ofnanostructures 412, 416, 420 corresponding to each nanolens 410, 414,418 are adapted to modulate light of a single wavelength or definedrange of wavelengths emitted from corresponding pixels 402, 404, 406.For example, the first plurality of nanostructures 412 disposed on thefirst nanolens 410 are adapted to reduce or eliminate chromaticaberrations and to compensate for an optical path length of red light atan image plane. The second plurality of nanostructures 416 disposed onthe second nanolens 414 are adapted to reduce or eliminate chromaticaberrations and to compensate for an optical path length of blue lightat the image plane. The third plurality of nanostructures 420 disposedon the third nanolens 418 are adapted to reduce or eliminate chromaticaberrations and compensate for an optical path length of green light atthe image plane. Thus, it is possible to form a focused image at theimage plane with light of varying wavelengths.

The nanolenses and nanostructures of each of the nanolenses 410, 414,418 and nanostructures 412, 416, 420, respectively, are formed from adielectric material, such as ZnO materials, TiO₂ materials, GaNmaterials, and combinations thereof. The dielectric material may bycrystalline or amorphous, depending upon the desired optical propertiesassociated different crystallographic lattice structures (or lackthereof). In one embodiment, each nanostructure of the plurality offirst nanostructures 412 disposed on the nanolenses 410 is fabricatedwith a substantially uniform first morphology. Each nanostructure of theplurality of second nanostructures 416 disposed on the nanolenses 414 isfabricated with a substantially uniform second morphology different fromthe first morphology. Each nanostructure of the plurality of thirdnanostructures 420 disposed on the nanolenses 418 is fabricated with asubstantially uniform third morphology different from the firstmorphology and the second morphology. In this embodiment, the firstmorphology is adapted to modulate red light, the second morphology isadapted to modulate blue light, and the third morphology is adapted tomodulate green light

While each of the first, second, and third morphologies are unique, themorphology of each of the nanostructures 412, 416, 420 may be columnar,pillar-like, cubic, or the like. A height, width, length, diameter,spacing, or other physical characteristic of the nanostructures 412,416, 420 are unique to the first, second, and third morphologies,respectively. In one embodiment, a width of each nanostructure of thenanostructures 412, 416, 420 is between about 50 nm and about 100 nm.

In another embodiment, a height of each nanostructure of thenanostructures 412, 416, 420 is an order of wavelength differentcorresponding to the light color being modulated by the nanolenses 410,414, 418, respectively. For example, a height of the nanostructures 412corresponds to a wavelength difference between red light emitted fromthe pixels 402 and blue and green light emitted from adjacent pixels404, 406, respectively. A height of the nanostructures 416 correspondsto a wavelength difference between blue light emitted from the pixels404 and red and green light emitted from adjacent pixels 402, 406,respectively. A height of the nanostructures 420 corresponds to awavelength difference between green light emitted from the pixels 406and red and blue light emitted from adjacent pixels 402, 404,respectively.

The nanostructures 412, 416, 420 are deposited by various techniquesdepending upon the type of dielectric material utilized to fabricate thenanostructures 412, 416, 420. Suitable deposition techniques includechemical vapor deposition, physical vapor deposition, molecular beamepitaxy and the like. Apparatus suitable for performing such depositionprocesses are tools available from Applied Materials, Inc., Santa Clara,Calif.

Patterning of dielectric films deposited to form the nanostructures 412,416, 420 includes processes such as nano-imprint lithography, e-beamlithography, or other lithographic techniques suitable for forming thenanostructures 412, 416, 420 with morphologies such as those describedabove. As such, monochromatic nanolenses with correspondingnanostructures may be formed in a manner unique to each of the pixels402, 404, 406. It is also contemplated that in addition to nanolenses asdescribed above, the embodiments described herein may be implemented inother light modulation devices, such as polarizers, wave retardationplates, and the like.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A display apparatus, comprising: a substrate; afirst pixel formed on the substrate; a first nanolens disposed on thefirst pixel; a second pixel formed on the substrate; a second nanolensdisposed on the second pixel; a third pixel formed on the substrate; anda third nanolens disposed on the third pixel, wherein each of the firstpixel, the second pixel, and the third pixel has a substantially uniformsize and distribution across the substrate.
 2. The apparatus of claim 1,wherein the first pixel is configured to generate light at a firstwavelength having a first bandwidth.
 3. The apparatus of claim 2,wherein the first pixel is configured to generate red light.
 4. Theapparatus of claim 3, wherein the first nanolens comprises a pluralityof first nanostructures.
 5. The apparatus of claim 4, wherein the firstnanostructures are adapted to compensate for an optical path length ofred light at an image plane.
 6. The apparatus of claim 2, wherein thesecond pixel is configured to generate light at a second wavelengthhaving a second bandwidth different from the first wavelength and thefirst bandwidth.
 7. The apparatus of claim 6, wherein the second pixelis configured to generate blue light.
 8. The apparatus of claim 7,wherein the second nanolens comprises a plurality of secondnanostructures.
 9. The apparatus of claim 8, wherein the secondnanostructures are adapted to compensate for an optical path length ofblue light at an image plane.
 10. The apparatus of claim 6, wherein thethird pixel is configured to generate light at a third wavelength havinga third bandwidth different from the first and second wavelength and thefirst and second bandwidth.
 11. The apparatus of claim 10, wherein thethird pixel is configured to generate green light.
 12. The apparatus ofclaim 11, wherein the third nanolens comprises a plurality of thirdnanostructures.
 13. The apparatus of claim 12, wherein the thirdnanostructures are adapted to compensate for an optical path length ofgreen light at an image plane.
 14. A display apparatus, comprising: asubstrate; a red light pixel formed on the substrate; a first nanolensdisposed on the red light pixel; a blue light pixel formed on thesubstrate; a second nanolens disposed on the blue light pixel; a greenlight pixel formed on the substrate; and a third nanolens disposed onthe green light pixel, wherein each of the red light pixel, the bluelight pixel, and the green light pixel have a unique size and uniformdistribution across the substrate.
 15. The apparatus of claim 14,wherein each of the red light pixel, the blue light pixel, and the greenlight pixel are quadrilateral shaped.
 16. The apparatus of claim 15,wherein each of the first nanolens, the second nanolens, and the thirdnanolens are sized and shaped to substantially correspond with the sizeand shape of the red light pixel, the blue light pixel, and the greenlight pixel, respectively.
 17. The apparatus of claim 14, wherein eachof the red light pixel, the blue light pixel, and the green light pixelare circular or oblong shaped.
 18. The apparatus of claim 17, whereineach of the first nanolens, the second nanolens, and the third nanolensare sized and shaped to substantially correspond with the size and shapeof the red light pixel, the blue light pixel, and the green light pixel,respectively.
 19. A display apparatus, comprising: a substrate; a firstpixel formed on the substrate; a first nanolens disposed on the firstpixel, the first nanolens comprising first dielectric nanostructuresadapted to compensate for an optical path length of red light at animage plane; a second pixel formed on the substrate; a second nanolensdisposed on the second pixel, the second nanolens comprising seconddielectric nanostructures adapted to compensate for an optical pathlength of blue light at the image plane; a third pixel formed on thesubstrate; and a third nanolens disposed on the third pixel, the thirdnanolens comprising third dielectric nanostructure adapted to compensatefor an optical path length of green light at the image plane.
 20. Theapparatus of claim 19, wherein each of the first, second, and thirddielectric nanostructures reduce or eliminate chromatic aberrations atthe image plane.